Automatically-regulated liquid rheostat operated by means of compressed air.



No. 821,418. PATENTED MAY 22, 1906.

C. DE KANDU.

AUTOMATICALLY REGULATED LIQUID RHEOSTAT OPERATED BY MEANS- OF COMPRESSED AIR. A A APPLIUATION FILED NOV. 27, 1903.

2 $HIZET$-SH1TET 1. 73 .1.

v 0. DB KAND6.

AUTOMATICALLY REGULATED LIQUID RHEOSTAT OPER 0P COMPRESSED AIR.

APPLICATION FILED NOV. 27, 1903.

ATED BY MEANS PATENTED MAY 22, 1908.

I v UNI ED STATES PATENT orrion.

2GOLOMAN DE 'KANDO, OF BUDAPEST, AUSTRIA-HUNGARY, ASSIGNOR To RAILWAY ELECTRIC POWER COMPANY, A CORPORATION OF MAINE. AUTOMATICALLY-REGULATED LIQUIDYRHEOSTAT OPERATED BY MEANS OF COMPRESSED All Specification of Letters Patent.

ratented M522, 1906.

Application filed November 27,1903. Serial No. 182,700.

To all whom it may concern: 1

Be it known that I, CQLOMAN DEKANDC'),

engineer, a subject of the Em eror of'Auscertain new and useful m rovements in or Relating to Automaticall egulated Liquid Rheostats Operated by eansof Compressed Air, of which the following is a full. and clear description.

My present invention relates to automatically-regulated liquid rheostats operatedby means of compressed air for starting and regulating the speed of induction-motors; and it'consists in certain novel parts and combination of parts particularly pointed out in the claims concluding thisspecification.

In the accom anying drawlngs I have diagrammaticallyi lustrated theleading features of my invention, which, with the following description, will enable those skilled in the art to practice the same; but it will beunderstood that-a variety of instrumentalities in detail maybe employed to embody the principles thereof without departing from the spirit of my invention and without exceedmg the $00 e-ofm claims. I

n the rawings, Figure 1 is a cross-sectional view of a aratus involving my present invention. 'g. 2 illustrates the connection of the apparatus shown in' Fig. 1.

The following is a description ofrthe drawin s.

is a liquid rheostat of a form now well known in the art' '(see my Patents No. 677,454, dated July 2, 1901, and N o. 733,97 dated July 21, 1903) comprising a reservoir 24 and a chamber.21,co ntaining the. electric terminals22, electrically connected by fluid discharged from the reservoir 24.

1 is the chamber containing compressed air.

16 is a handle. controlling the valve 0, which when moved in the direction of the arrow first establishes communication between the compressed-air chamber 1 and the chamber 14 andwhen moved farther compresses the spring 3. 21s .a :valve pressed upon its seat by a spring 25.

- 4 is amembrane supporting an abutment controlled by the s ring 3, the compression of which is regulate by a rack 26. 1'

27 isca chamber the membrane 4.

between the valve 2 and' 28 is a ipe' leading from the chamber 27 to the cham er 29. 'The chamber 29 is provided at its topl with amembrane 6 andat its bottom wit a membrane 5 of smaller area. These membranes carry a valve-case 9 and a spring-controlled valve'32, terminating in a projection 7. I

11 is a pivoted armature within the influence of an electromagnet or solenoid 12, the active wire of which is included in the circuit of the field or armature of an induction-motor.

1 13 is a valve controlling communication between thechamber 17 and the reservoir 24, which valve is controlled by a float 30.

15 is a piston controlled by the pressure of thereto a device'forshort-circuiting the secondary of an induction-motor when full speed is attained.

describe When the starting-lever 16 is moved in the direction of the arrow, the valve 0 establishes communication between compressed-air chamber 1 and chamber .14; but this air cannot at once pass into the chamber 17, because the valve 8 is at this time held down b the projection 7, attached to it. When tie lever 16 is moved still farther in the direction of the arrow, the spring 3 is compressed, and the valve 2- is thereby opened, admitting compressed air into the c amber 27 through conduit 28 to the chamber'29. The pressure of the air in the cham ber 29 acting u on the membranes 5 and 6, the upper one eing of larger area, elevates the cas1ng)9,' which is attached to both membranes, ecause it produces inflation of or toward the larger membrane 6,) so that the projection. 7, being thus elevated, opening valve ,8 and allowing the compressed air from chamber 14 to pass into chamber 17, and the valve 13 beingxat this time 0 en into the reservoir 24 of t e rheostat. reservoir is thus forced into the chamber 21 and, rising in said chamber, establishes elec' trical contact between theplates 22. As soon as the li uid reaches the bottom of said plates current l)e ins to fiow through the motor 50, Fig. 2, an throulggi the solenoid or magnet 12, the effect of w h is to attract the armaair in the chamber 17 and having attached The operation of the device may be thus he fluid in this,

ber 21 rises is thus automatically controlled by balancing the current flowing against the pressure of the air within the chamber 29. When the liquid-level in the chamber 21 rises to a certain point, or, in other words, when the liquid-level in chamber 24 falls to a given point, the float 3O permits valve 13 to close and prevents the admission of any further quantity of compressed ainto the chamber 24, and hence prevents any further decrease of resistancein the motor-circuit. Up to this time the pressure in the chamber 17 is relatively slight, corresponding approximately only to the differences of levels of the liquid in the rheostat-chambers. It new., however, rapidly rises to maximum pressure, and in so doing actuates the short-circuiting device 34 and 15, connected in the circuit of the secondary of the motor, and normal or fulls eed running conditions are established.

ould any loss of pressure occur through leakage from the chamber 24, it will automatically be compensated by the further admission of compressed air through the valve 13, as will be readily understood. Automatic regulation also takes place when the currentflow increases so rapidly that the armature 11 is depressed too quickly, since in this case the valve 32 is opened, thus discharging the compressed air lnto the outer atmosphere, whereupon the normal or automatic regulation through the valve 8 continues to take its course, as described. The pressure of the air in chamber 27, and hence the pressure in chamber 29, which is in free communication therewith, is determined by the degree to which the spring 3 is compressed, or, in other words, by the position of the handle 16, since the abutment 33 is controlled as to position by the degree of compression of the spring 3, acting against the pressure of compressed air within the chamber 27 upon the diaphragm 4. Assuming a given degree of compression of the spring 3, the position of the valve 2 will be determined by the pressure in the chamber 27, since when a certain pressure is reachedsay the pressure exerted by the spring 3said valve will close. Since the degree of pressure in the chamber 29 acting, as it does, against the force of the armature 11 determines the position of the valve 8, and therefore the admission of compressed air to the rheostat, it is plain that the speed with which the liquid. rises in the rheostat (which corresponds with the speed with which the resistance diminishes in the motor) is determined by the position of the controller-han dle 16, and it is also plain that with the ham dle in a given position the starting-current is maintaincdconstant, while the resistance in the armature-circuit varies.

. In stopping the motor the handle 16 is moved in the reversedirection, as will be readily understood. When the spring ,3 is released, the pressure in chamber 27 forces the abutment 33 outwardly away from the inner end of double valve 2, and thus opening com munication with the outside air.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. A liquid rheostat combined with a supply of compressed air, a throttle-valve between said compressed-air supply and said rheostat adapted to control the supply of compressed air to the rheostat; said valve being controlled by the combined action of the electric current flowing through said rheostat and compressed-air pressure.

2. A liquid rheostat combined with a supply of compressed air, a throttle-valve between said cornpressed-air supply and said rheostat adapted to vary the rate of supply of compressed air to the rheostat; said valve being controlled by the combined action of the electric current flowing through said rheostat and compressed air.

3. A liquid rheostat combined with a supply of compressed air, a hand-operated valve for controlling the connection between said supply and sad rheostat, a throttle-valve located in said connection, an electric device in circuit with said rheostat, a device operated by air-pressure and operating in opposition to said electric device to control the action of said throttle-valve.

4. A liquid rheostat combined with a supply of compressed air, a hand-operated valve for controlling the connection between said supply and said rheostat, a throttle-valve located. in said connection and a supplemental device operated by compressed air to control the action of the throttle-valve.

5. A liquid rheostat combined with a supply of compressed air, a hand-operated valve for controlling the connection between said supply and saidrheostat, a throttle-valve lo 'cated in said connection, a device normally holding said throttle-valve closed and means for actuating said. device to permit said thrcttle-valve to open.

6. A liquid rheostat combined with a supply of compressed. air, a throttle-valve located in the connection between said rheostat and .said compressed-air supply, a supplemental device operated by compressed air for controlling the position of said throttle valve, a hand-operated valve for controlling the connection between said supply and said rheostat and also for controlling the flow of compressed air to said sup lemental device.

7. A liquid rheostat com ined with a supply of compressed air, a throttle-valve located 1n the connection between said rheostat I and said compressed-air supply, a supplemental device operated by compressed air for controlling the position of said throttlevalve and a hand-operated device which initially controls the connection between said supply nd said rheostat and subsequently IIO controls the connection between said supply and said supplemental device. a 8. In combination with. a liquid rheostat, a

supply of compressed air, an electric device in circuit with said rheostat and a throttlevalve in the connection between the compressed-air supply and the rheostat, of a de vice controlling said throttle-valve comprising a chamber having flexible walls of unequal area". I

In combinationwitha liquid rheostat, a supply ot-compressed air, an electricdevice n plrcuit with said rheostat and a throttle vice controlling said throttle-value and are lief passage controlled by a cheek-valve.

11'. In combination with an uid rhe'ostat,

in circuit with said rheostat and a throttlevalve in the connection between the compressed-air supply and said rheostat, of a device controlling said throttle-valve, a checkvalve controlling a passage communicating with the compressed-air chamber of the rheostat and the open air.

12. A liquid rheostat combined with a supply of compressed air, a throttle-valve between said compressed-air supply and said rheostat, adapted to control the supply of compressed air to said rheostat, said valve being controlled by the combined action of a io'rce automatically exerted by the current lowing opposed by "variable force under the control of the operator.

13. A liquid rheostat combined with a supply of compressed air, a throttle-valve between said compressed-air supply and said rheostat, adapted to" control the supply of compressed air to the rheostat, said valve being controlledby the combined action of the electric current flowing through said rheostat, and compressed-air pressure with mechanism controlled by the operator for varying said compressed-air pressure. 1

14. In combination with a liquid rheostat, a supply of compressed air, a device in circuit with said rheostat operated by the current ,fiowing, a throttle-valve in the connection between the compressed-air supply and the rheostat, of a chamber having flexible walls of an equal area whereby the pressure of air within the same opposes the force exerted by the current to close the throttlevalve, and mechanism under the control of the operator whereby the pressure within said chamber may be varied. I

15. The combination with an electric motor of a starting resistance, means for varying said resistance, said means being controlled by an electrically-operated device in the circuit of the motor, a mechanically-operatedv device acting in opposition thereto, I and means for adjusting said mechanicallya supply of compressed air, an e ectric device operated device whereby the rate of variation of the starting resistance is controlled. 16. A starting-rheostat for induction-motors comprising a variable resistance interosed in the secondary of the motor, means for automatically diminishing said resistance vas the speed of the motor increases, a device actuated by the current flowing to maintain the starting-current of substantially constant p value while the resistance is changing and means for variably controlling said constantcurrent value.

In witness whereof I have hereunto set my hand in the presence of two witnesses.

I COLOMAN DE KAN'DG. Witnesses:

EUGENE HAnsAnvs, T. LA GUARDIA. 

